My first ‘real’ job was doing research in a financial publishing house, Euromoney Publications, in London. After a while checking facts and keying in figures for a database, I progressed to writing up market reports for publication to deadline.
That was where I first learned about rules or guidelines on style and grammar. Being a language graduate, I diligently applied house rules to my writing. I instinctively knew they were important for consistency, accuracy and clarity in grammar and punctuation.
I got an excellent grounding in writing skills in that first job and apply many of those principles in my writing and editing work to this day. While certain clients have particular house styles, I am generally guided by the following rules or conventions. (Naturally, I use either American or British spelling and style depending on the client, but that is a topic for a separate discussion.)